The conveyor track in escalators is moved depending on the usage need. So-called standby operation is used for this purpose. If passengers do not come to an escalator, a photoelectric cell or a corresponding sensor does not give a signal, and the speed of the conveyor track is decreased from the rated speed (e.g. 0.65 m/s) after a delay time (e.g. 1 min) to creeping speed (typically 0.2 m/s) and further after a certain delay time (e.g. 5 min), the conveyor track stops. Always when a passenger arrives at the escalator, the control of the escalator increases the speed to the rated speed and the operating chain starts from the beginning. If the delay times of the stand-by function are set reasonably, the function saves energy, the service life of the escalator lengthens and the servicing need decreases. In most applications the use varies e.g. according to the times of day. A problem has been that e.g. on staircases traveling upwards from the platform level of a metro during peak hours it is almost certain that passengers will come very soon after a decrease of speed. In this case the decrease of speed would not, therefore, be necessary. Correspondingly, during very quiet times of day a staircase has been kept running for the amount of the delay time, although the probability of a next passenger arriving is low. A result of these is a large amount of stops, starts or unnecessary instances of being kept running, which has shortened the service life of the conveyor, increased energy consumption and shortened servicing intervals. The delay times have been set to be of certain lengths, and left permanently at those lengths. The set values of a delay time are not normally changed after commissioning, but if the value needs to be rectified, a serviceman must stop the conveyor and shift to the control panel to manually rectify the set value.
Known in the art are solutions wherein a travelator is self-learning or it is otherwise controlled based on historical data. For example, in a solution known from patent publication JP2004224548A, starting and stopping can be performed according to the arrival of a train at a station or the departure of a train from a station. In these solutions the speed of the escalator has thus been changed on other bases than the delay time that has passed since the last user. If a measurement of the delay time from the last passenger were used concurrently in the types of escalators referred to above, for changing the speed on the basis of the delay time, the delay time in these solutions would also be constant in the manner of prior art. In these respects, therefore, the avoidance of unnecessary changes of speed during operation is still ineffective.